The present invention deals with administering a therapeutic agent, such as a drug. More specifically, the present invention is directed to delivering the therapeutic agent directly to heart tissue in a noninvasive manner.
Iontophoresis can be used to administer a therapeutic agent, such as a drug or other medication or agent. Iontophoresis typically involves an interaction between ionized molecules of a drug (or other therapeutic agent) and an external electric field. This interaction results in the migration of charged molecules. The migration is accomplished by placing two electrodes across the tissue to be treated and charging the electrodes with a relatively low, direct current (DC), voltage. One of the electrodes acts as a source electrode and is typically in contact with the drug solution. The other electrode acts as a return electrode and may be filled with an electrolyte solution. The electric field generated between the two electrodes causes the charged molecules in the therapeutic agent to migrate from one electrode into the tissues to be treated.
This addresses a disadvantage associated with injected therapeutic agents. Iontophoresis tends to diffuse the drug throughout the treated tissue whereas an injection masses a concentrated bolus of drug within the tissue or joint, potentially causing damage to the tissue.
Similarly, delivery of drugs by iontophoresis avoids a disadvantage which comes with oral administration of medication. The disadvantage is known as first-pass metabolism of the drug. When a drug is taken orally and absorbed from the digestive tract into the blood stream, the blood containing the drug first passes through the liver before entering the vasculature where it will be delivered to the tissue to be treated. However, the liver is a metabolically active organ. Thus, much of the orally ingested drug may be metabolically inactivated before it has a chance to exert its pharmacological affect.
Various drug therapies have also been developed to treat coronary disease. Such therapies often require the delivery of drugs, or other treatment material (i.e., a therapeutic agent) to the myocardium, a vessel, or any other organ or area for which transluminal access is desirable. For example, anti-arrythmia drugs may be desirably administered to the myocardium. Similarly, recent advancements and pharmaceutical developments have resulted in gene therapy drugs, such as growth factors, which can be administered to the myocardium for myocardial revascularization. Such therapies have been used in place of, and in conjunction with, other more conventional therapies, such as percutaneous transluminal coronary angioplasty (PTCA), bypass techniques, and atherectory techniques.
The present invention is drawn to delivering a therapeutic agent (such as a drug or other treatment material) to the myocardium, a vessel, or any other organ or area for which transluminal access is desirable. For example, the present invention can be used to administer anti-arrythmia drugs to the myocardium for electrophysiological therapy. Similarly, growth factors and other gene therapy substances can be administered to the myocardium, using the present invention, for myocardial revascularization.
A therapeutic agent is delivered to heart tissue in a body. The therapeutic agent is introduced to a first side of the heart tissue. An electrode is percutaneously located on a second side of the heart tissue. The electrode is energized to induce migration of the therapeutic agent into the heart tissue.